Interstitial Site Occupation in a-LaNi5-H Studied by Deep Inelastic Neutron Scattering

Abstract

Deep inelastic neutron scattering (DINS) from hydrogen is a new technique made possible by the advent of accelerator-based neutron sources such as ISIS at the Rutherford Appleton Laboratory. DINS measures both the concentration and the mean kinetic energy of hydrogen in the sample. H concentrations of less than 1% relative to the metal can be measured, since the hydrogen signal is well separated from the metal signal. In situ measurements on un-cycled α-LaNi5-H revealed that the sample contained trapped hydrogen after desorption. The changes in H concentration measured with DINS were in good agreement with manometric measurements. The H kinetic energy did not change significantly with concentration, suggesting that the trapped and untrapped H atoms occupy essentially the same interstices.